The invention relates to a hose arrangement for a water-conveying system, having a flexible pressure hose and a connection piece arranged on one hose end of the pressure hose, wherein the connection piece has at least one hose nipple which engages in the pressure hose, and a ferrule which engages around the outside of the pressure hose, and wherein the pressure hose is held in a force- and/or form-fitting manner between the hose nipple and the ferrule, wherein the ferrule projects beyond the hose nipple by way of a sleeve portion at the hose-side nipple end of said nipple in the direction of extent of the pressure hose, and wherein the ferrule forms, in the sleeve portion, a radially inwardly directed protrusion which acts radially on and displaces the pressure hose such that, compared with the clear inside diameter of the relaxed pressure hose, the clear inside diameter of the pressure hose in the region of the sleeve portion is close to or equal to the clear inside diameter of the hose nipple.
Hose arrangements of this kind are known and have frequently proved successful when used in pressurized, water-conveying systems. The designation “fitting” is also common for the hose nipple, while the designation “crimp sleeve” is also used for the ferrule when the pressure hose is held on the hose nipple by crimping of the ferrule.
A quick coupling for connecting a fluid line to a multi-layer flexible hose line is previously known from U.S. Pat. No. 4,303,263. The previously known quick coupling has a coupling part having an insertion opening coaxial with the flow line. Inserted in this insertion opening is an insert which carries a hose nipple in its end region remote from the coupling part, it being possible to push the one hose end of the multi-layer flexible hose onto said hose nipple. The coupling part has an external thread, onto which a sleeve-like coupling collar having an internal thread can be screwed. Provided in the coupling collar is a holding ring, the ring opening of which widens conically in the direction of the coupling part such that when the coupling collar is pushed onto the coupling part, the hose line gripped at the inner circumference of the holding ring is likewise pushed onto the hose nipple with its hose end increasing in size and is held there in a secured manner.
The quick coupling previously known from U.S. Pat. No. 4,303,263 allows the, if required also rapidly, releasable connection of the hose end of a flexible hose line to the hose nipple of the quick coupling, since, in the case of the previously known quick coupling, a crimpable ferrule is dispensed with. However, a disadvantage is the complex structure of this quick coupling, with its many coordinated constituent parts, resulting in a correspondingly high weight and large diameter of the quick coupling. However, compact hose arrangements which have a simple structure and are correspondingly space-saving are frequently preferred in sanitary hose lines, said hose arrangements also allowing use in confined space conditions, for example on the underside of a wash basin in the region of the fastening of the sanitary outlet fitting.
A hose arrangement of the type mentioned at the beginning is already known from DE 29 07 813 A1, said hose arrangement being provided as a high-pressure hose fitting. The previously known hose arrangement has a flexible pressure hose and a connection piece which is arranged on one hose end of the pressure hose. Provided on the connection piece is a hose nipple which engages in the hose end of the pressure hose. The pressure hose is held between the hose nipple and the ferrule in a force- and form-fitting manner, said ferrule engaging around the outside of the pressure hose. The ferrule projects beyond the hose nipple by way of a sleeve portion at the hose side nipple end of said nipple in the direction of extent of the pressure hose. On its sleeve inner circumference, the ferrule has a large number of spaced apart and annularly encircling protrusions which, in the manner of a barb, allow the hose end only to be pushed on into the intermediate space formed between the ferrule and the hose nipple, but oppose any removal of the hose end from this intermediate space. These protrusions, which are provided on the ferrule also in the region of the projecting sleeve portion, form radially inwardly directed formations which act radially on the pressure hose over the longitudinal extent thereof and displace it such that, compared with the clear inside diameter of the relaxed pressure hose, the clear inside diameter of the pressure hose in the region of the sleeve portion is close to or equal to the clear inside diameter of the hose nipple.
The high-pressure hose fitting previously known from DE 29 07 813 A1 presupposes a comparatively thick pressure hose made of elastic material, which is able, along its longitudinal extent, to even out protrusions acting from the outside so well that a virtually uniform clear flow cross section is established in each case in the region of the ferrule acting on the pressure hose. However, although pressure hoses which have a relatively large wall thickness and a relatively small clear flow cross section compared therewith are suitable as high-pressure hoses, they are less suitable for sanitary water conduits through which a possibly also large quantity of water per unit time is intended to flow.
It is known that the flow properties of such a hose arrangement are limited by the internal geometry of the hose nipple, such that the inside diameter of the hose nipple frequently has to be dimensioned in such a way that as little hindrance as possible of the flow arises in the area of application.